Juniper MX Series

Chapter Review Answers

1. Answer: C. By default, filter and policer stats are aggregated on a per PFE basis, unless you use the interface-specific statement. When the interface-specific keyword is used a separate filter (and if used, policer) instance is created for each application.

2. Answer: E, both A and C. A physical interface policer needs the physical-interface-policer statement, and you apply via one or more filters that include the physical-interface-filter statement, under each family on all the IFLs that share the interface device. The result is a single policer that polices all families on all IFLs.

3. Answer: E. All are true regarding a Layer 2 policer, which is also a form of logical interface policer in that it acts on all families that share an IFL.

4. Answer: A. When a routing instance has filter applied to an lo0 unit in that instance, that filter is used; otherwise, control plane traffic from the instance to the RE is filtered by the main instance lo0.0 filter.

5. Answer: B. You use prefix lists and the apply-path feature to build a dynamic list of prefixes that are defined somewhere else on the router; for example, those assigned to interfaces or used in BGP peer definitions, and then use the dynamic list as a match condition in a filter to simplify filter management in the face of new interface or peer definitions.

6. Answer: B. Only with next-term can you can have traffic that has been accepted by one policer, which is then returned to the calling term where it’s normally implicitly ...